CA1193399A

CA1193399A - Stable water glass solutions, process for their preparation and use for organosilicate foams as well as a production process therefor

Info

Publication number: CA1193399A
Application number: CA000432865A
Authority: CA
Inventors: Peter Horn; Robert Gehm; Matthias Marx; Artur Roeber
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1982-07-23
Filing date: 1983-07-21
Publication date: 1985-09-10
Also published as: DE3381557D1; DE3227580A1; US4447561A; EP0099531A2; EP0099531A3; EP0099531B1; ATE52744T1

Abstract

Abstract of the Disclosure Stable water glass solutions are obtained (A) by mixing a solution of an aqueous alkali silicate solution and alkali hydroxide with a tertiary amine and subsequently oxyalkylating the resultant two-phase reaction mixture with at least one alkylene oxide in such an amount that a uniform solution forms or (B) by oxyalkylating a tertiary amine with at least one alkylene oxide and mixing the resultant reaction mixture with a solution of an aqueous alkali silicate solution and alkali hydroxide.

The stable water glass solutions are suitable for the preparation of organo silicate foams.

For the preparation of the organo silicate foams, a mixture of the stable water glass solutions and tertiary amino group-containing polyether polyols is reacted with organic polyisocyanates in the presence of catalysts, blowing agents and optionally auxiliaries and additives.

Description

Case 1384 STABLE WATER GLASS SOLUTIONS, PROCESS FOR
THEIR PREPARATION AND USE FOR ORGANOSILICATE
FOAMS AS WELL AS A PRODUCTION PROCESS THEREFOR
~ackground of the Invention 1. Field of the Invention This invention relates to a process for oxyalky-lating aqueous alkali silicate solutions containing an alkali hydroxide and a tertiary amine. More particularly, the invention relates to oxyalkylated water glass solutions, a process for their preparation and organosilicate foams prepared Erom them.

2. Prior Art The preparation of rigid or flexible inorganic-organic plastics is known.
According to data in French Patents 1,362,003 and 1,419,552, foam~ which can be used as insulation material are prepared based on alkali silicates, polyisocyanates and natural or synthetic resins.
According to German Published Application 17 70 384 (U. S. 3,607,794), silicon-containing products are further obtained by reacting aqueous solutions of an alkali silicate with an organic isocyanate or isothiocyanate.
In order to accelerate the reaction between the water glass solution and the organic polyisocyanates, catalysts are described in German Published Application 24 60 834 (U. S. 4,136,238) which have a Zwitter ion structure.

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The drawback of these processes is that gel-like deposit~ are formed even during tha mixing process of the components resulting in process and equipment difficulties during the processing and which may result in nonhomogeneous plastics.
According to German Publ.ished Application 2,227,147 (U. S0 4,097,423), the polyisocyanates are replaced by terminal isocyanate group containing prepolymer ionomers having 2 to 200 milliequivalants per 100 grams of ionic groups in order to avoid these drawbacks. Since the prepolymer ionomers must be prepared in an additional process step, this method is expensive. Another drawbac]c iq the fact that the products frequently have viscositie~ above 2000 mPas and at times up to 100,000 mPas and more at 25C
so that they cannot be processed directly. In order to reduce the viscosity, the prepolymer ionomers must be diluted with additives, for example, solvents or lo~
viscosity isocyanates. This, however, again results in prolonged curing times~
According to data in European published applica-tion 579 (U. S. 4,276,404~, the organic polyisocyanates are initially reacted with an aqueous basic solution or suspen~
sion of the inorganic compounds resulting in a primary dispersion. Subsequently, flowable inorganic compounds and optionally catalysts and additives are .incorporated in this

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pri~ary dispersion resulting in a final dispersion n This process is cumber30me and technically diffîcult to accom-plish.
The purpose of this invention was to develop stable components for the preparation of organo silicate foams which can be processed using commonly employed device~
for the polyurethane foam preparation.
Surprisingly, this requirement could be met by u~ing stable water glass ~olution~ which are obtained by (A~ Mixing (a) a solution of (i) 100 parts by weight of an aqueous alkali silicate 301ution and (ii) 1.5 to 20 part~s by weight~ preferably 3 to 15 parts by weight of an alkali hydroxide with (b) 2 to 12 parts by weight, preferably 3 to 6 parts by weight, of a tertiary amine and sub~equent oxyalkylation as the resultant two-phase reaction mixture with (c) at least one mole, preferably 1 to 10 moles, and particularly 1 to 3 moles of at least one alkylene oxide per mole of tertiary amine or (B) Oxyalkala~ion of `\

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~a) 2 to 12 parts by weight, preferably 3 to 6 parts by weight, of a tertiary a~ine with (b) at least one mole/ preferably l to lO moles, and particularly l to 3 moles of at least one alkylene oxide per mole of tertiary amine and mixing of the resultant reaction mixture with (c) a solution of (i) lO0 parts by weight of an aqueous alkali silicate solution and (ii~ 1.5 to 20 parts by weight, preferably 3 to 15 parts by weight of alkali hydroxide.

Description of the Preferred E~bodiments The water glass solutions according to this invention are ~table and can be mixed with the other component~ for the preparation o~ organosilicate foams without silicic acids or other compounds being precipitated.
In a simple and reproducible manner, guaranteeing a uniform course of the polyurethane reaction, and cross~
linking of the water glass, largely open-celled organo-silicate foams can be produced from the water glass solu-tions according to this invention analogous with the polyurethane foam technology. With densities of preferably 7 to 20 grams per liter, the resultant substances are extremely light and essentially do not shrink. Even without ~333~

the addition of common flame retardants, the organo silicate foams are essentially flame retardant and particularly have an extremely low gas density.
We should like to state the following pertaining to the compon~nts suitable for use as the stable water glass solutions and the raw materials for the preparation of the organo silicate foams:
Suitable for the preparation of the stable water glass ~olution according to this invention are aqueous alkali silicate solutions having the formula M2o.Sio2 in which M is an alkali metal, for example, potassium or, preferably, sodium, and wherein the mole ratio of M20:Sio2 is greater than one, preferably 1.6 to 4, and particulary 2 to 3.6 and whereln the density is 28 to 60Be, preferably 35 to 41Be. Aqueous sodium silicate solutionq wikh mole ratios of Na20:SiO2 of 2 to 3.6 and densities of 3B to 40 Be have proven to work well and are, therefore, used on a preferred basis.
One hundred parts by weight of the above-mentioned aqueous alkali silicate solu~ions are treated with 1.5 to 20 parts by weight, preferably 3 to 15 parts by weight, of alkali hydroxide, for example, potassium hydroxide or, preferably, sodium hydroxide The alkali hydroxides are used preferably in the form of aqueous solutions, the concentration of which can be varied widely as a function of ` ~

the den~ity of the alkali silicate solution. Suitable examples include 30 to 80 percent by weight, preferably ~0 to 60 percent by weight, aqueous alkali hydroxide solutions with approximately 50 percent by weight aqueous sodium hydroxide solutions being preferred.
Suitable tertiary amines include compounds normally used ~or accelerating the blowing reaction, that is, compounds which are used for the formation of carbon dioxide from polyisocyanate and water for the preparation of polyurethane foams. Examples include tertiary polyamines, tertiary aminoalkylethers and/or N,N-dialkylalkanolamines which are optionally used in combination with metal nitrates ~uch as zinc and/or copper nitrate. Preferably used are N,N,N',N'-tetramethyl-di-(2-aminoethyl)ether, N,N',N',N",N"-pentamethyl diethylenetriamine and/or N,N-dimethylethanol-amine. The ~ertiary amine~ are u~ed in amount~ of 2 to 12 parts by weight, preferably 3 to 6 parts by wei~ht per 100 parts by weight of aqueous alkali silicate solution.
Suitable alkylene oxides include 2,3-epoxy-propanol-l and, preferably, ethylene oxide, 1,2-propylene oxide or their mixtures~ For the oxyalkylation, at least one mole, preferably 1 to 10 moles, and particularly 1 to 3 moles of alkylene oxide or alkylene oxide mixture are u3ed per mole of tertiary amine. The stable water glass solu-tions of this invention can be prepared by various methods. According to the preferably u~ed method A, the solution of aqueous alkali silicate sollltion and alkali hydroxide, advantageously aqueous sodium hydroxide solution, is mixed with the tertiary amine at temp2ratures of 0C to 50C while being stirred. This results in a two-phase reaction mixture which is oxyalkylated with at least one alkylene oxide, preferably ethylene oxide, at temperatures of 10C to 100C, preferably of 10C to S0C, while being stirred until a homogeneous solution has been obtained.
This requires the quantities of a7kylene oxide mentioned above.
According to another mode of operation, the tertiary amine is initially mixed wlth at least one alkylene oxide, preferably ethylene oxide, at temperatures of 10C to 100C, preferably of 10C to 50C, while being stirred and the resultant reaction mixture is ~ixed with the solution of aqueous alkali silicate 301ution and alkali hydroxide while being stirred at temperatures of 10C to 100C, preferably 10C to 60C. It may also be advantageous to carry out the oxyalkylation under pressure, for example, at 1 to 10 bars, preferably 2 to 7 bars, and optionally in the presence of inert gas, preferably nitrogen.
The stable water glass solutions of this invention are preferably used for the preparation of organosilicate foams.

~ ~ 9339a31 For the preparation of the organosilicate foams, the starting ~aterials are rea~ted employing well-known methods in polyurethane foam chemistry, preferably as two-component systems, using the one-shot method.
Referred to as the A component is a reaction mixture which contains catalysts and optionally physical blowing agents, auxîliaries and additives in addition to the compounds with reactive hydrogen atoms and the B-component comprises the organic polyisocyanates which may optionally be mixed with physical blowing agents, auxiliaries and addi tives.
Suitable compounds with reactive hydrogen atoms include the stable water glass solutions of thi~ invention which are mixed with tertiary amino group-containing polyether polyols for the preparation of the organosilicate foams. Suitable mixtures contain 1 to 20 parts by weight, preferably 2 to 8 parts by weight, of the amino group-containing polyether polyols per 100 parts by weight of water glass solution. Other common polyether polyols may optionally al~o be used such as polyols with functionalities of 2 to 8, preferably 3 to 6, and hydroxyl numbers of 30 to 800, preferably of 40 to 700, hydroxyl group-containing polymers with functionalities of 2 to 6 and hydroxyl numbers of 50 to 400 such as hydroxyl group-containing polyesters, polyester amides, polyacetals and polycarbonates a~ well as chain e~tenders and/or crosslinking agents.

The tertiary amino group-containing polyether polyols to be u~ed in accordance with tnis invention which contain at least one, preferably 1 to 5, tertiary amino groups as bridge members in bonded form in the polyoxyalky-lene chain have hydroxyl numbers of 200 to 800, preferably of 400 to 700, and functionalities of 2 to 5, preferably of 3 to 4. The products may be prepared in accordance with known methods from one or more alkylene oxide with 2 to 4 carbon atoms in the alkylene radical and an amino group-containing initiator molecule which contains in bonded form 2 to 5, preferably 3 to 4, active hydrogen atoms. Suitable alkylene oxides include 1,2- and/or 2,3-butylene oxide and preferably ethylene oxide and l,2-propylene oxide. The alkylene oxides may be used individually, alternatingly in sequence or as mixtures. Suitable amino group-containing initiator molecules include, for example: ammonia, hydra-zine, N-mono and N,N'- and/or N,N-dialkylhydrazines ~ith 1 to 6 carbon atoms in the alkyl radical, optionally N-mono-, N,N- and N,N'-dialkyl substituted diamines with 1 to 6 carbon atoms in the alkyl radical, such as ethylenediamine, 1,2- and 1,3-propylenediamine, 1,4-butylenediamine, 1,6-hexamethylenediamine, 2,4- and 2,6-toluenediamine, 4,4'-, 2,4'- and 2,2'-diaminodiphenylmethane as well as the corresponding distillation residues as they are obtained after distilling pure diamines from the reaction mixtures, _ g _ 3~

amino alcohols such as mono-~ di-- or trialkanolamines, dialkylenetriamines, trialkylenel:etramines and oligomeric polyalkylene polyamines. Preferably used as amino group-containing initiator molecules are ethylenediamine, 1,4-butylenediamine, 1,6-hexamethylenediamine as well as the corresponding distillation reqidue, triethanolamine and diethylenetriamine.
The tertiary amino group-containing polyether polyols may be used alone or in mixtures. They may also be mixed with commonly used, that i5 r non-nitrogen containing polyether polyols or hydroxyl group-containing polymers of the above-mentioned type.
Mixtures which have proven to worX well consist of 50 to approximately 100 percent by weight, preferably 70 to 97 percent by weight, based on the total weight of the mixture of at least one tertiary amino group-containing polyether ~olyol and from about 0 to 50 percent by weight, preferably 3 to 30 percent by weight, based on the overall weight of the mixture of a non-nitrogen containing polyether polyol or another hydroxyl group-containing polymer.
The commonly used polye~her polyols are prepared according to known methods from one or more of the above-mentioned alky~ene oxides and at least one nitrogen-free initiator molecule with 2 to 8, preferably 2 to 3, reactive hydrogen atoms. Suitable initator molecules include:

water, phosphoric acid, polycarboxylic acids, particularly dicarboxylic acids such as adipic acid, succinic acid, phthalic acid and terephthalic acid and preferably polyhy-droxyl compounds such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, pentaerythritol, sorbitol, sucrose and preferably glycerin and trimethylol-propane.
As already mentioned, hydroxyl group-containing polyesters, polyester a~ides, polyacetals and polycarbonates are suitable hydroxyl group-containing polymers~ The hydroxyl group-containing polyesters may be prepared, for example, from dicarboxylic acids, preferably aliphatic dicarboxylic acids with 2 to 12, preferably 4 to 8, carbon atoms in the alkylene radical and multiunctional alcohols, preferably d.iolsq Examples include aliphatic dicarboxylic acids such as glutaric acid, pimelic acid, subaric acid, azelaic acid, sebacic acid, undecaneclioic acid, dodecane-dioic acid and preferably succinic and adipic acid and aromatic dicarboxylic acids such as phthalic acid and terephthalic acid. Examples of bi- or multifunctional, particularly bi- and trifunctional alcohols are ethylene glycol, diethylene glycol, 1,2-propylene glycol, trimethy-lene glycol, dipropylene glycol, l,10-decanediol, glycerin, trimethylolpropane and preferably l,4-butanediol and 1,6-hexanediol.

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The polyester amides include, for example, the predominantly linear condensates with reactive hydrogen atoms obtained from multifunctional saturated and/or unsatu-rated carboxylic acids and/or their anhydrides and multi-functional saturated and/or unsaturated amino alcohols or mixtures of multifunctional alcohols and amino alcohols and/or polyamines.
Suitable hydroxyl group-containing polyacetals include, for example, those compounds prepared from glycols such as diethylene glycol, triethylene glycol, 4,4'-di(2-hydroxyethoxy)diphenyldimethylmethane, hexane diol and formaldehyde. Suitable polyacetals may also be prepared by polymerizing cyclic acetals.
Possible carbonates including hydroxyl groups are those of the basically known type which may be prepared, for example, hy reacting diols such as 1,3-propanediol 1,4-butanediol and/or 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol with diaryl carbonateq, for example, diphenyl carbonate or phosgene.
In order to achieve specific mechanical proper-ties, it may be advantageous to also use chain e~tenders and/or cross-linking agents for the preparation of the organo silicate foams in addition to the already mentioned water glass solutions, polyether polyols containing tertiary amino groups and, optionally, nitrogen group free polyether polyols and/or hydroxyl group containing polymers. ~uch substances include polyfunctional, particularly di- and trifunctional compounds with molecular weights o~ 17 to 600, preferably 60 to 300. Employed, for example, are di- and trialkanolamines such as diethanol~mine and triethanolamine, aliphatic and aromatic diamines such as ethylenediamine, 1,4-butylenediamine, 1,6-hexamethylenediamine, 4,4'-diamino-diphenylmethane, 3,3'-dialkyl substituted 4,4'-diaminodi-phenylmethanes, optionally 3,5-dialkyl substituted 2,4- and 2,6-toluene diamine and preferably aliphatic diols and triols w.ith 2 to 6 carbon atoms such as ethylene glycol, 1,4-butanediol, 1,6-hexanediol, glycerin and trimethylol-propane.
In order to accelerate the reaction between the compounds with reactive hydrogen atoms and polyisocyanates, commonly u~ed polyurethane cataly3ts are added to the reaction mixture or preferably to the A-component in an amount of 0.01 to 10 parts by weight, preferably of 0.1 to 3 parts by weight per 100 parts by weight of the mixture of stable water giass solutions and tertiary amino group-containing polyether polyols. Preferably used are basic polyurethane catalysts, for example, tertiary amines such as dimethylbenzylamine, dicyclohexylmethylamine, dimethylcyclo-hexylamine, N,N,N',N'-tetramethyldiaminoethylether, bis(di-methylaminopropyl)urea, N-me~hyl- and/or N-ethylmorpholine, ~ 13 -dimethylpiperazine, pyridine, 1,2-dimethylimidazole, 1-azabicyclo(3,3,0)octane, dimethylaminGethanol, N,N',N"-tris(dialkylaminoalkyl~hexahydrotriazines such as N,NI,N''-tris(dimethylaminopropyl)-s-hexahydrotriazine and particu-larly triethylenediamine and triethanolamine. Moreover, metal salts such as iron~(II)-chloride, zinc chloride, lead octoate and preferably tin salts such as tin dioctoate, tin diethylhexoate and dibutyl tin dilaurate are also suit able. These ar~ generally used in combination with the basic polyurethane cataly~t~.
Suitable blowing agent~ are particularly carbon dioxide which is formed during the reaction of water with the organic polyisocyanate~. Mixtures of physical blowing agents with water which ars preferably incorporated in the A-component may also be used. It may optionally also be advantageou~ to mix the organic polyisocyanate with the phy~ical blowing agent thereby reducing the viscosity of the B-component.
Suited as physical blowing agents are liquids which are inert with respect to the inorganic polyisocya nates and whic'n have boiling points below 100C, preferably below 50C, and particularly between 50C and +30C under atmospheric pressure so that they evaporate under the influence of the exothermal polyaddition and polycondensa-tion reaction. Examples of such preferably used liquids are hydrocarbons such as pentane, n- and iso-butane and propane, ethers such as dimethylether and diethylether, ketones such as acetone and methylethyl ketone, ethylacetate and prefer-ably halogenated hydrocarbons such as methylene chloride, trichlorofluoromethane, dichlorodifluoromethane, dichloro-monofluoromethane, dichlorotetrafluoroethane and 1,1,2-trichloro-1,2,2-trifluoroethane. Mixtures of these low boiling liquids with each other and/or with other substi-tuted or unsubstituted hydrocarbons may also be used.
The amount of physical blowing agents required in addition to water can be determined simply as a function of the desired foam den~ity and amounts of approximately 1 to 50 parts by weight, preferably 3 to 40 parts by weight per lOO parts by weight of the mixture of water gla3s solution and tertiary amino group-containing polyether polyols may be employed.
The ~-component advantageously consi.sts of the organic polyisocyanates. Examples for suitable materials or this purpo~e include aliphatic, cycloaliphatic, ali-phatic-aromatic and preferably aromatic multifunctional isocyanates. Detailed examples include: aliphatic diisocy-anates such as ethylene, 1,4-tetramethylene, l,6-hexamethy-lene and 1,12-dodecane diisocyanates, cycloaliphatic diisocyanates such as cyclohexane-1,3- and 1,4-diisocyanates as well as any desired mixtures of these isomers, l-isocya-~3~

nato-3,3,5-trimethyl-5-isocyanatomethyl-cyclohexane, 2,4-and 2,6-hexahydrotoluene diisocyanate as well as any desired mixtures of these isomers, 4,4'- and 2/4l-diisocyanato dicyclohexylmethane, aromatic diisocyanates such as 1,3- and 1,4-phenylene diisocyanate, 2,4- and 2,6- toluene diisocya-nate as well as any desired mixtures of these isomers, 2,2'-, 2,4'- and 4,4'-diphenylmethane diisocyanate and naphthalene-1,5-diisocyanate and aromatic polyisocyanates such as 4,4',4"-triphenylmethane triisocyanate, 2,4,6-triisocyanatobenzene and polyphenylene polymethylene polyisocyanates.
Modified polyisocyanates such as carbodiimide group-containing polyisocyanates (German Patent 10 92 007), allophanate group-containing polyisocyanates (British Patent 994,890, Belgium Patent 761,626), isocyanurate group-containing polyisocyanates (German Patent 10 22 789, German Patent 12 22 067, German Paterlt 10 27 394, German Published Application 19 29 034 and German Published Applicatior 20 04 048), urethane group-containing polyisocyanates (Belgium Patent 752,261, U. S~ Patent 3,394,164), biuret group-containing polyisocyanates (German Patent 11 01 394, British Patent 889,050) and ester group-containing polyiso-cyanates (Briti~h Patent 965,474, British Patent 10 72 956, U. S. Patent 3,567,763, German Patent 12 31 688) may also be used.

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Preferably used are the industrially available aromatic di- and polyisocyanates such as 2,4- and 2,6-toluene diisocyanate a~ well as any desired mixtures of these isomers, 2,2'-, 2,4'- and 4,~l-diphenylmethane diisocyanate as well as any desired mixtures of these isomers, mixtures of 2,2' , 2,4'-, 4,4' diphenylmethane diisocyanates and polyphenylene polymethylene polyisocya-nates (crude MDI) and mixtures o toluene diisocyanates and crude MDI as well as urethane and i~ocyanurate group-containing polyisocyanates. The mentioned di- and polyiso-cyanates may be used individually or in the form of mix tures.
Auxiliaries and additives may also be incorporated in the reaction mixture, preferably the A-component.
Examples include stabilizers, hydroly~is protection agents, pore regulators, fungistats and bacteriostats, dye~, picJments, fillers, surfactants, plasticizers and flame retardants.
Suitable examples include surfactants which promote the homogenization of the starting substances and which are optionally also suited for regula~ing the cell structure of the foams. Examples include siloxane-oxyalky-lene mixed polyalkylphencls, oxyethylated fatty alcohols, paraffin oils, castor oil and/or ricinoleic acid esters and Turkish Red oil which are used in amounts of 0.2 to 8, preferably 0.5 to 5 parts by weight per lOO parts by weight of the mixture of water gla~s solution and tertiary amino group-containing polyether polyols.
It may also be advantageous to incorporate a plasticizer in the reaction mixture so that the tendency toward brittleness in the products i9 reduced. Commonly used plasticizers may be used, but it is particularly advantageous to use such substances which contain phos-phorous and/or halogen atoms and which thereby further lo increase the flame resistance of the organo silicate foams. Such substances include tricresylphosphate, tris-2-chloroethylphosphate, tris-chloropropylphosphate and tris-2,3-dibromopropylphosphate.
Fillers include: organic fillers such as mel-amine, carbon and carbon fibers and inorganic fillers, for example, silicate-containing minerals such as antigorite, serpentine, horn blends, amphiboles, chrisotile, talcum and Transpafill, metal oxides such as kaolin, titanium oxide and iron oxides, metal salts such as chalk and heavy spar as well as glass. Special mention should also be made of inorganic pigments such as cadmium sulfide and zinc sulfide and flame retardants such as melamine and aluminum oxide hydrate.
More detailed data concerning the above-mentioned other commonly applied additives are contained in the ~333~

appropriate literature, for example, in the monograph by J. H. Saunders and K. C. Frisch, "High Polymers t ~I vol . XVI, Polyurethanes, Parts 1 and 2, Interscience Publishers, 1962 and/or 1964.
For preparing the organo silicate foams, the compounds are reacted with reactive hydrogen atoms and organic polyisocyanates in such quantities that the charac teristic number is 2 to 30, preferably 4 to 15. The characteristic number in this case is defined as Isocyanate amount (actual) x 100 Isocyanate amount (calculated) The organo silicate foams are preferably prepared according to the one-shot method. It has been proven to be particularly effestive to combine the starting materials into two components with the A component, as already described, preferably containing the compounds with the reactive hydrogen atoms, the catalysts, the blowing agents, auxiliaries and additives and the B-component preferably consisting of the organic isocyanate. This method is used on a preferred basis.
The advantage of this method consists of the fact that the A- and B-components may be transported in a space-saving manner and can be stored for a limited period of time and only require intensive mixing in the mentioned quantity ratios at temperatures to 10C to 50C, preferably 15C to 30C, prior to the preparation of the organo silicate foam3. The reaction mixture is then allowed to foam in open or closed molds with compression ratios of 1.2 to 8, preferably of 2 to 4, generally being used for foaming in closed molds.
The organo qilicate foams produced in accordance with thi~ invention have densities of 4 to 150 grams per liter, preferably 7 to 20 grams per liter, show essentially no tendency towards shrinkage and excel by their extensive open-celled nature, good flame resistance and extremely low smoke gas density.
As a re~ult of the good flow properties of the unfoamed reaction mixture and the low pressure development during foaming, the products are particularly well suited for filling thin sandwich elements with foam. The products are also used in the mining industry and in the construction industry for filling out hollow spaces and as light foams.

Example 1 Preparation of the stable water gl~s~ solution:
To a reactor was added 82.0 kg of aqueous sodium silicate solution (SiO2:Na20 = 1:3.44) at 38 to 40Be and initially mixed with 7.13 kg of a 50 percen~ by weight aqueous sodiu~ hydroxide solution and subsequently with 3.56 kg of N,N,N',N'-te~ramethyl-di-(2-aminoethyl)ether at 25C
while being stirred. For a period of 0.5 hour, 1.88 kg of ethylene oxide gas was introduced into the resultant two-phase reaction mixture at 25C while the mixture was being stirred. In order to complete the reaction, the mixture was then stirred for an additional three hours. A clear, stable solution wa~ produced.
Example 2 Employing the procedure of Example 1, the following components and amounts were used: 867.0 grams of aqueous sodium silicate solution (SiO2:Na20 = 1:3.44) at 38Be to 40Be, 75.4 grams of 50 percent by weight aqueous sodium hydroxide solution, 37.6 grams N,N,N',N'-tetramethyl-di-(2-aminoethyl)ether and a mixture of 10 grams of ethylene oxide and 16 grams of 1,2-propylene oxide.
A clear, stable solution was obtained.

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Example 3 A clear, stable solution was also obtained when the procedure of Example 2 was employed with a mixture of ethylene oxide and 1,2-propylene oxide being replaced by 33~2 grams of 2,3-epoxy-propanol-1.
Example 4 An amount of 320 grams of N,N,N',N'-tetramethyl-di-(2-aminoethyl)ether was mixed with 496 grams of water in a round flask equipped with a cooled drip funnel, agitator and reflux cooler and 176 grams of ethylene oxide were added to this solution within one hour while the mixtures were being stirred. The reaction temperature was maintained at a maximum of 45C by external cooling. In order to complete the reaction, the mixture was then stirred for an additional hour at 25C.
A portion of this product, 117.8 grams, was stirred into a solution consi3ting of 76 grams of a 50 percent by weight aqueous sodium hydroxide solution and 826.8 grams aqueous sodium silicate solution (SiO2:Na20 -1:3.44) at 38 to 40Be at a temperature of 25C. A clear, stable solution was obtained.

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Example 5 Preparation of the organo silicate foams:
A-component: a mixture o.' 160 grams of the water gla~s ~olution prepared in accordance with Example 1, 40 grams of water, 8 grams of silicone stablizer DC 190 made by ~ow Corning Corporation, 4 grams of triethylamine, 6 grams of a tertiary amino group-containing polyether polyol having a hydroxyl number of 563 prepared by the propoxylation of the column bottoms of the hexamethylenediamine distillation and 60 grams of trichlorofluoromethane was prepared.
B-component: a mixture of 200 grams of a mixture of diphenylmethane dii~ocyanates and polyphenyl polymethy-lene polyisocyanates (i~ocyanate content 31 percent by weight) and 20 grams of tris-chloroethylphosphate was prepared.
One thousand one hundred twelve grams of the A-component and 880 gram~ of the B-component were mixed by means of an agitator at a speed of 1648 rpm at 25C for 10 second~O The reaction mixture was then introduced into a polyethylene foil bag having a diameter of 60 centimeters and a height of 100 centimeters and was allowed to foam~
The product had the following properties:

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Cream time: 18 seconds Rise time: 53 second~
Bulk density (kg/m3): 12~7 Compression strenyth according to DIN 53 420 ~N/mm2): 14.7 Sag at break according to DIN 53 423 (mm): 39.7 Flex strength at maximum deflection according to DIN 53 420 (k.Pa): 16.4 Dimensional stability when cold at -30~C according to AGK 7 Deviation - length (%): -0.1 Deviation - width ( %): 0.0 Deviation - thickness (%) 0.0 Dimensional stability when heated at 110C for 16 hours according to Deviation - length (~): -0.7 Deviation - width (~): -0.7 Deviation - thickness (%): 0.0 Burning behavior according to NOTE: The resultant organo silicate foam was fine celled and abrasion resistant~

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Claims

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. A stable water glass solution obtained by A) Mixing a) a solution of i) 100 parts by weight of an aqueous alkali-silicate solution, and ii) 1.5 to 20 parts by weight of an alkali hydroxide with b) 2 to 12 parts by weight of a tertiary amine, and subsequent oxyalkylation of the resultant two-phase reaction mixture with c) at least one mole of an alkylene oxide per mole of tertiary amine, or B) by oxyalkylation of a) 2 to 12 parts by weight of a tertiary amine with b) at least one mole of an alkylene oxide per mole of tertiary amine and mixing of the resultant mixture with c) a solution of i) 100 parts by weight of an aqueous alkali-silicate solution, and ii) 1.5 to 20 parts by weight of alkali hydroxide.

2. The stable water glass solution of claim 1 wherein aqueous sodium and/or potassium water glass solu-tions with 28 to 60°Be are used as the aqueous alkali sililcate solutions.

3. The stable water glass solution of claim 1 wherein aqueous 40 to 60 percent by weight sodium and/or potassium hydroxide solutions are used as the alkali hydroxides.

4. The stable water glass solutions of claim 1 wherein the tertiary amines are selected from the group consisting of N,N,N',N'-tetramethyl-di(-2-aminoethyl)-ether, N,N',N',N",N"-pentamethyl-diethylenetriamine and N,N-di-methylethanolamine and mixtures thereof.

5. The stable water glass solutions of claim 1 wherein ethylene oxide and/or propylene oxide are used as the alkylene oxides.

6. A process for the preparation of stable water glass solutions wherein A) a) a solution of (i) 100 parts by weight of an aqueous alkali silicate solution, and ii) 1.5 to 20 parts by weight of an alkali hydroxide are mixed with b) 2 to 12 parts by weight of a tertiary amine and the resultant two-phase reaction mixture is oxyalky-lated with c) at least one mole of an alkylene oxide per mole of tertiary amine at temperatures of 0°C to 100°C
while stirring, or B) b) 2 to 12 parts by weight of a tertiary amine are oxyalkylated with c) at least one mole of an alkylene oxide per mole of tertiary amine at temperatures of 0°C to 100°C and the resultant mixture is mixed with a) a solution of i) 100 parts by weight of an aqueous alkali-silicate solution, and ii) 1.5 to 20 parts by weight of alkali hydroxide at temperatures of 10°C to 100°C.

7. A process for the preparation of organosili-cate foam by reacting an organic polyisocyanate and a compound with reactive hydrogen atoms in the presence of catalysts, blowing agents, and optionally auxiliaries and additives, wherein the mixtures of stable water glass solutions of claim 1 and tertiary amino group containing polyether polyols are used as compounds with reactive hydrogen atoms.

8. The process of claim 7 wherein a polyether polyol with a functionality of 2 to 5 and a hydroxyl number of 200 to 800 containing 1 to 20 parts by weight of tertiary amino groups is used per 100 parts by weight of stable water glass solutions.

9. The process of claim 7 wherein the character-istic number is 2 to 30.

10. The product of claim 7.

11. The product of claim 8.

12. The product of claim 9.